1. Field of the Invention
Embodiments of the present invention generally relate to a method and apparatus for capacitive sensing, and more specifically, an adaptive touch sensing electrode.
2. Description of the Related Art
Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones).
A proximity sensor device typically includes sensor electrodes that are driven with signals for capacitive sensing. Receiver circuitry receives resulting signals from the sensor electrodes for determining positional information of one or more input objects near the proximity sensor device, if any are present. The receiver circuitry generally has a dynamic range that determines the range of signal strengths of the resulting signals from which meaningful positional information may be derived. If the dynamic range of receiver circuitry is exceeded, meaningful data may not be extracted from signals received as a result of driving the sensor electrode for capacitive sensing.
As the foregoing illustrates, what is needed in the art are techniques for improving utilization of the dynamic range of receiver circuitry in a proximity sensor device.